1. Field of the Invention
The present invention relates generally to Long Term Evolution (LTE)-Advanced mobile communication systems, and more particularly, to a handover between a macro base station and a home base station in LTE-Advanced mobile communication systems.
2. Description of the Related Art
LTE-Advanced mobile communication systems incorporate the use of a Home Node B (HNB), which acts as a femto cell and is optimized for deployment in a home. Through the use of HNBs in LTE-Advanced systems, network capacity and performance are expected to significantly increase. However, the incorporation of HNBs in a system currently requires the use of a complicated network protocol, because each HNB is used in a manner similar to that of a base station. Thus, technological advancements are required that enable handovers to HNBs in the LTE-Advanced system.
Conventionally, a terminal requests a handover from a macro base station to an HNB, after the terminal compares a receiving power of the macro base station to a receiving power of the HNB.
An HNB performs the same function as a macro base station, but on a smaller scale. Thus, an unregistered terminal in close proximity to an HNB may experience greater interference when communicating with its own HNB or the macro base station. For example, when each cell controls its own power and a receiving power of a registered terminal decreases, the HNB is able to increase its transmitting power. However, by increasing transmitting power, interference with unregistered terminals in close proximity to the HNB also increases, thereby negatively affecting the performance of the macro base station.
An HNB may be installed in each house, resulting in a large number of HNBs that are in close proximity, e.g., in a crowded neighborhood or an apartment complex. Therefore, when a terminal is moving it may experience a large number of handovers. The increased number of handovers results in increased processing and signaling in the network, thereby decreasing network throughput.
Further, when a terminal performs its own searches for registration and handover to HNBs, processing performance of the terminal decreases due to the frequent measurement and management that is required.